Compressed gas circuit breaker having a spherical metal reservoir forming part of an arcing gap



1 Nov. 16, 1965 a. BILLON ETAL 3,

COMPRESSED GAS CIRCUIT BREAKER HAVING A SPHERICAL METAL RESERVOIR FORMING PART OF AN ARCING GAP Filed July 5. 1965 United States Patent 3,218,422 COMPRESSED GAS CIRCUIT BREAKER HAVING A SPHERICAL METAL RESERVOIR FORMING PART OF AN ARCING GAP Grard Billon and Jean-Claude Henry, Grenoble, France, assignors to Etablissements Merlin & Gerin, Societe Anonyme, Grenoble, France Filed July 5, 1963, Ser. No. 293,073 Claims priority, application France July 10, 1962 4 Claims. (Cl. 200148) This invention relates to compressed gas circuit breakers and more particularly to a compressed gas circuit breaker having a spherical metal reservoir which contains acompressed gas.

When the circuit breaker is subjected to an excess voltage which is very large, for example an excess voltage produced by atmospheric conditions, its level of insulation may be exceeded and a flash-over may take place. This flash-over can occur at various points of the apparatus. Particularly in the case where the circuit breaker is open, the flash-over may lead to a bridging or traversing of the apparatus.

It is important to be in a position to define as precisely as possible the dielectric level between the entry and the outlet of a circuit breaker so as to be able to adjust it to the level of protection which the lightning arrester devices provide.

As a general rule the level of resistance to impact waves between the entry and the outlet of a circuit breaker depends on the polarity of the wave and on the side where the wave is applied, because the electric fields are very different from the uniform fields.

It is therefore an object of the invention to provide a circuit breaker of the type mentioned above whose resistance to the impact waves is clearly defined and which is substantially independent of the polarity of this wave.

It is a further object of the invention to avoid the flash-over between the contacts on the inside of the interrupting chamber, as such flash-overs could cause the explosion of the chamber.

It is already known to shunt the interrupting chambers with horn gaps, or needlepoint gaps or with gaps between small spheres. These exterior spark gaps are practically inoperative due to their large flash-over delay, and the flash-over taking place on the inside of the interrupting chambers between the open contacts.

According to the invention the spherical metallic reservoir which contains compressed gas constitutes one electrode of a spark gap having a very small flash-over delay and shunting the interrupting chamber on the outside.

The interrupting period is thus shunted by a spark gap between spheres having a very small flash-over delay and whose operation is to a very large degree independent of the polarity of the excess voltage wave and of the side where this wave is applied. The spark gap thus formed may be adjusted to a value which is smaller than the level of the interrupting period and the insulating level between the entry and the outlet is defined precisely and may be adjusted without difficulty to the lightning arrester devices which protect the entire installation.

The following description of a few embodiments of the invention is not intended to limit the generic scope of the invention by the details indicated or to the particular details of the embodiments chosen for the purpose of illustration.

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In the attached drawing the figures show diagrammatically compressed gas circuit breakers having a spherical reservoir and provided with spark gaps according to the invention, and in which:

FIGURE 1 is a side elevation of the circuit breaker according to the invention in which a single interrupting chamber is supported by the gas reservoir;

FIGURE 2 is a side elevation of the circuit breaker according to the invention in which two parallel interrupting chambers are supported by the gas reservoir;

FIGURE 3 is a side elevation of the circuit breaker according to the invention in which two parallel aligned interrupting chambers are supported by the gas reservoir.

FIGURE 1 of the drawing shows a circuit breaker in which the compressed gas reservoir 11 is spherical and supports an interrupting chamber 12 in which the main contacts are located. The reservoir is of a metallic material and constitutes one of the two poles of the circuit breaker. The other pole 13 is electrically connected to a sphere 14, shown as substantially smaller than the reservoir 11, by means of an electrical connection 15. The spark gap is constituted of the spheres 11 and 14 and its flash-over voltage may be defined with great precision. This voltage is substantially the same for the two polarities of impact waves and the flash-over delay is very small and in any case well below that of a horn gap or needlepoint gap.

In the example of FIGURE 2 the spherical metallic reservoir 11a supports two interrupting chambers 12a and 12b which are parallel but their axes are ofiset one with respect to the other. The terminals 13a and 1312 are connected to the spheres 14a and 14b by electrical connections 15a and 15b, all respectively. The chamber 12a is thus protected by the spark gap 14a-11a and chamber 12b is protected by the spark gap 14b-11a.

In the example of FIGURE 3, the reservoir 11b supports two chambers 12c and 12d whose longitudinal axes coincide. The terminals 13c and 13d are connected to the spheres 14c and 14d by connections 15c and 15d, all .respectively, in a manner analogous to that of FIGURE 2 described above.

It will be understood that the spherical electrodes 14, 14a, 14b, 14c, 14d may be replaced by electrodes which have a dilferent profile and which may be especially designed with a view to obtaining a uniform electric field providing a small flash-over delay and a negligible polarity efiect.

What is claimed is:

1. In a compressed gas circuit breaker having an arcing gap, in combination a substantially spherical metallic reservoir containing compressed gas, at least one insulator supported by said reservoir and defining an interrupting chamber having two poles, an electrode disposed in spaced relationship to and externally of said reservoir, said reservoir being electrically connected to one pole of said chamber and said electrode being electrically connected to the other pole of said chamber, said spherical reservoir and said electrode forming an arcing gap having a short flash-over delay.

2. A circuit breaker according to claim 1 wherein said electrode is also spherical.

3. A compressed gas circuit breaker having an arcing gap comprising a substantially spherical metallic reservoir containing a compressed gas, an insulator supported by said reservoir defining an interrupting chamber containing a pair of spaced poles, one of said poles being electrically connected to said reservoir; an electrode supported by said insulator, substantially smaller than said reservoir, electrically connected with the other of said poles, disposed externally of said reservoir and spaced therefrom to form an arcing gap therewith.

4. A compressed gas circuit breaker according to claim 3 wherein said electrode is substantially spherical.

4 References Cited by the Examiner UNITED STATES PATENTS 2,155,841 4/1939 Rorden 3l7-14 5 KATHLEEN H. CLAFFY, Primary Examiner.

BERNARD A. GILHEANY, Examiner. 

1. IN A COMPRESSED GAS CIRCUIT BREAKER HAVING AN ARCING GAP, IN COMBINATION A SUBSTANTIALLY SPHERICAL METALLIC RESERVOIR CONTAINING COMPRESSED GAS, AT LEAST ONE INSULATOR SUPPORTED BY SAID RESERVOIR AND DEFINING AN INTERRUPTING CHAMBER HAVING TWO POLES, AN ELECTRODE DISPOSED IN SPACED RELATIONSHIP TO AND EXTERNALLY OF SAID RESERVOIR, SAID RESERVOIR BEING ELECTRICALLY CONNECTED TO ONE POLE OF SAID CHAMBER AND SAID ELECTRODE BEING ELECTRICALLY CONNECTED TO THE OTHER POLE OF SAID CHAMBER, AND SPHERICAL RESERVOIR AND SAID ELECTRODE FORMING AN ARCING GAP HAVING A SHORT FLASH-OVER DELAY. 